Finding the Fourth Proportional to 1,401.89, 1,934.58 and 780.89

Step by Step Solution

1. Step 1: Write the proportion equation
   1,401.89 : 1,934.58 = 780.89 : x
2. Step 2: Convert to fraction form
   1,401.89/1,934.58 = 780.89/x
3. Step 3: Cross multiply
   1,401.89x = 1,934.58 × 780.89
4. Step 4: Simplify right side
   1,401.89x = 1,510,694.18
5. Step 5: Solve for x
   x = 1,510,694.18/1,401.89
6. Step 6: Final answer
   x = 1,077.61